Optically active α-aminophosphonic acid derivatives are useful for the synthesis of candidate compounds of pharmaceutical drugs such as antibacterial agents, anti-HIV drugs, and enzyme inhibitors (see, for example, NPLs 1 to 5).
Generally employed methods for producing optically active α-aminophosphonic acid derivatives are, for example, methods using chiral auxiliary groups for increasing stereoselectivity (see, for example, NPLs 6 to 9).
These techniques, however, use expensive chiral auxiliary groups in a large amount (an equimolar amount or more) and the chiral auxiliary groups cannot be recovered after use, having a problem that they are not economical.
Other proposed production methods include a method using, as a catalyst, Cinchona Alkaloid such as quinine, adding diphenyl phosphate to a specific ketimine to obtain an adduct, and synthesizing an optically active α-aminophosphonic acid derivative from the adduct (see, for example, NPL 10).
This technique, however, has a problem that stereoselectivity is low unless at least one of two substituents binding to carbon of the C═N bond of the ketimine is an aromatic hydrocarbon group, which imposes limitation on synthesized optically active α-aminophosphonic acid derivatives.
At present, therefore, there is a need for a novel production method capable of synthesizing various optically active α-aminophosphonic acid derivatives without using chiral compounds in a large amount.